The purpose of this study is to obtain data necessary to characterize the elimination of RE104 and metabolites from breastmilk of health lactating volunteers to support a regulatory assessment of when mothers can safely return to breastfeeding following a single-dose of RE104 for Injection.

Inclusion Criteria:

• Females between 18 and 45 years of age, at least 50 kgs, and a body mass index of 18-34 kg/m2
• Has been breastfeeding or actively pumping for at least 4 weeks postpartum
• Agrees to cease breastfeeding for duration of study (Day 14) and confirms infant is able to feed from a bottle at screening.
• Willing and able to pump in order to maintain sufficient milk supply volumes for the study
• Is not pregnant or planning to become pregnant during the study
• Able to understand and adhere to study schedule and requirements and willing to sign an ICF
• In good general health as determined by medical history, clinical laboratory test results, vital sign measurements, 12-lead ECG results, and physical examination findings at screening

Exclusion Criteria:

• Has mastitis or other condition that would prevent the collection of milk from one or both breasts
• Active or medical history of significant mental disorder (including but not necessarily limited to major depression and anxiety disorders, bipolar disorder, schizophrenia, schizoaffective disorder, psychotic disorder and/or borderline personality disorder), or first-degree family history of psychosis or bipolar disorder
• Medically significant condition or other concomitant condition or history rendering unsuitability for the study, in the judgement of the investigator
• Has used or intends to use of prohibited medications
• Has a known sensitivity or intolerance to hallucinogenic or psychedelic substances, or potential rescue medications

Data sharing will be consistent with the results submission policy of ClinicalTrials.gov.